The invention relates to a method and device for producing melt-spun continuous threads.
In the production of melt-spun continuous threads, the problem exists that the threads that are not further treated come apart as they are drawn off and drafted on the galettes; that is, the individual filaments come apart, and individual threads mix with one another. This has an adverse effect on the smooth travel of the thread, the maximum possible capacity of a galette, and in multicolor threads, the clarity of the individual colors.
From European Patent Disclosure EP 0 485 871 B1, a method and a device have become known in which differently dyed partial threads, after a preparation, are individually precompacted, drafted individually on galettes, and then jointly textured, compacted, and wound onto a bobbin; the precompacting is reversed again during the drafting. The goal of the precompacting is said to be that the partial threads have a certain cohesion during processing, and the finished yarn has clearly distinguishable colors.
In European Patent Disclosure EP 0 784 109 A2, a method and a device for creating a multicolor yarn are described, in which differently dyed partial threads or partial threads to be dyed differently are treated in such a way that before a final compacting done jointly, the partial threads are separated again, individually subjected to a further so-called postcompacting, then united, compacted and wound onto a bobbin. Once again, the goal is to attain compactness of the partial threads and different colors in the yarn.
The known methods have a number of disadvantages. Compacting is usually done by means of compressed air; this type of energy is very expensive, so that the production costs for the threads increase sharply with the number of compacting operations. A first compactor is disposed immediately downstream of the preparer; the effect is that by the compacting, some of the preparation agent is forced out of the thread and thus lost to the production process. Also, this portion of the preparation agent is atomized because of the action of the compressed air; because this presents a health risk to workers and a risk to the environment, this mist must be caught and disposed of. Finally, the knots created by the compacting lead to nonhomogeneity and interfere with the drafting.
The invention is suitable for producing various yarn qualities, such as BCF (carpet fiber; textile fibers, industrial yarns) and FDY. The process includes at least the steps of spinning and cooling the filaments as well as preparation and drawing off of the filaments combined into partial threads. Depending on the later use, such steds as drafting, texturing, compacting, bobbin winding, and so forth are added either individually or in combination. In these remarks, xe2x80x9cfilamentxe2x80x9d describes a single fiber, while xe2x80x9cthreadxe2x80x9d and xe2x80x9cyarnxe2x80x9d mean many filaments, joined together. A thread or yarn can be assembled from a plurality of partial threads that are processed separately before being joined together.
The object of the invention is to disclose a method for producing melt-spun continuous threads, in which with minimal use of aids such as compressed air and preparation agent, optimal thread travel on the galettes is attained with simultaneous high capacity, better performance in further handling steps such as drafting and texturing, and in the case of multicolor threads, high color contrast. Another object is to create a device for performing the method of the invention.
The preparation of a thread is performed in at least two stations, which are spaced apart from one another, in each case with a partial quantity of the total preparation agent required; the second preparer is disposed downstream of the first draw-off device. The preparation agent that is applied at a first station accordingly has enough time to penetrate far into the thread and to be distributed in it; this process is reinforced especially at the deflection at the draw-off device, where the thread undergoes fulling. The second preparer has the effect that the preparation agent overall can be applied maximally uniformly to the entire surface of all the filaments, without any substantial excess. This promotes the heat transfer between the thread and galettes as well as the further processing, such as drafting. A thread maintains a compact shape without coming apart. As a result, it is possible for many threads to be drawn over one galette, and/or to use a high wrap number, without requiring compacting. At the same time, very high thread speeds are possible. The risk of filament breakage is reduced.
Disposing the second preparer immediately upstream of the drafting has the advantage that an optimal heat transfer on the galettes can be achieved.
Limiting the quantity of preparation agent prevents losses and environmental impairment from ejection of the agent from the thread.
The preparation agents with an optimal effect for the subsequent method steps can be employed.
Claim 5 attains the second object.